A duality between cost and production is established for a firm subject to rate-of-return regulation. To this end, a rate-of-return regulated production function is defined and shown to exist. It is then shown how information regarding the unregulated technology can be obtained from the...

In this paper we show that in order to aggregate individual efficiency scores into a group (e.g., industry) efficiency score in such a way that the multiplicative structure of further decompositions is preserved with equal weights across components, the weighted geometric mean is required. We...